Rats and monkeys will be chronically exposed to oxidant air pollutants, primarily ozone, at concentrations approximating high ambient levels (0.2-0.5 ppm). A multidisciplinary group will make integrated biochemical, microbiological, physiological and morphological evaluations of effects. The findings will have relevance to the specific problem of air pollution and to a general understanding of pulmonary pathobiology. By plotting the relative levels of sensitivity of the various parameters studied, and the effects observed, a basis will be provided for making predictions of possible long-term consequences of photochemical smog on man. Comparison of effects in rats and monkeys should provide for more confident extrapolation to man and hence enable the setting of rational air quality criteria. A primary goal is to test critical hypotheses concerning biochemical, immunological and cellular mechanisms responsible for the deleterious effects of the pollutants. Major pathogenetic and modifying factors of interest are: the role of lipid peroxidation in initiating damage; the induction of antioxidant defense mechanisms by continued exposure and the general phenomenon of adaptation; the sites of impairment in pulmonary alveolar macrophages and components of the immune system in the lung; the sequence and nature of lesions resulting in the development of chronic obstructive lung disease (bronchitis/emphysema) and interstitial fibrosis. An additional goal is to explore further the potential prophylactic value for human populations of dietary antioxidants such as vitamin E and selenium.